1. Field of the Invention
This invention is generally directed to electro-mechanical locks of the type which are designed to be utilized on doors and gates associated with security areas including fences surrounding prison confinement areas, restricted access security zones and other enclosures wherein controlled access is required. Such locks are remotely controllable from a plurality of check point or guard areas and are sufficiently durable to withstand adverse environmental conditions and remain fully operable. The locks of the present invention include interchangeable latching assemblies which are in a "block" configuration so as to be utilizable with either sliding or swinging gates including gates mounted to slide or swing from the left or the right side of an opening thereby allowing a universal application of the latching mechanism of the locks regardless of the existing configuration of the door or gate to which the locks are to be installed.
2. Description of the Related Art
There have been many locks designed for use on chain link and steel fences and walls which extend around high security enclosures such as prisons. In a typical prison installation, the security locks are installed in what is referred to as a "Sally" port. A "Sally" port usually includes a combination of four or more gates located in two parallel fences. There are two gates for pedestrian access and two gates for vehicular access. If there are more gates they are usually for pedestrians to enter the area between the fences or a control room. The security locks are controlled remotely from a guard tower or a control room. In most installations the locks can be controlled from a plurality of locations.
In a typical high security area there will be many instances wherein the access locks are constantly exposed to environmental elements. In a prison installation the perimeter fences around the facility are cleared of all vegetation and overhead cover or screening. This exposes the locks directly to the elements and in many instances leads to premature failure of locking mechanisms either due to exposure to dirt and debris or to environmental conditions such as rain or ice.
In a high security area, when a person has been cleared to enter a facility, an outside gate is opened and the person is allowed to enter into a confinement area between enclosures or fences. After passing through the outer gate, the outer gate is closed and locked and an inner gate is opened allowing the person to pass through the inner gate into the enclosure. This same type of double entry access is provided for vehicular traffic. In the event of power failure, the locking mechanisms for the gates must be controllable manually. Further, in order to be secure, the locks of the outer and inner gates must be controlled so that when one of the locks is open, the remaining locks remain closed. In a typical "Sally" port installation, when one of the locks of the four gates is open none of the remaining gates can be opened. It is therefore necessary for the locks to contain sensors that indicate that a particular gate is closed and locked in a secured or latched position. When these conditions are met, other locks in the "Sally" port can be selectively opened.
Most security locks utilized in prison and other high security areas currently use a "shot" pin latching mechanism. The gate or door to be locked includes a tongue having an opening therein. When the gate or door is closed, a lock pin drops through the opening in the tongue thereby preventing the gate or door from being moved relative to the lock. When it is desired to open the gate, typically, a solenoid or mechanical lock linkage is utilized to engage and lift the "shot" pin from the opening in the tongue thereby releasing the door or gate for opening.
Experience with prior art locks has pointed to several problems. The most frequent problem is the need to hold the latching pin in a raised position while a gate or door is open. Some of the prior art locks use a complicated lever and latch to hold the latch pin up after it is initially lifted by a solenoid or mechanical linkage. It is, however, possible to trip the control circuit and drop the pin while the gate is open. If the latch pin is dropped when the gate is open, and the gate or door is closed, the tongue associated with the gate or door will engage the pin and, in many instances, cause damage to the pin. When the pin is damaged it can not be withdrawn and thereafter latched in a proper position within the opening of the tongue associated with the door or gate. If a lock is faulty, the area being controlled is no longer secured.
In prior art latching mechanisms that utilize a solenoid to retain a latch in an engaged position, there are other problems which have been experienced. For instance, a guard controlling such solenoid operated locks may have to continuously push switches that activate the solenoids and retain them in an "on" condition. In many instances, continually activating the solenoid to an "on" condition results in excessive use of the solenoid which can result in premature failure of the solenoid. In addition, the requirement to continuously activate a switch to control the latch by the solenoid may require that the attention of the guard, or other individual controlling the gate, be directed from making other observations which may be associated with their duties.
Another problem inherent in prior art security locking mechanisms is that they are not designed to be interchangeable. Therefore, specific locks must be manufactured for installation with respect to swinging doors and sliding doors and further consideration must be given to manufacturing locks to accept locking tongues which are installed on doors or gates which are either slidable or pivoted from their left or right side depending on installation requirements. As there has been no consideration given to providing a locking mechanism which offers universal installation with respect to left or right hand sliding or swinging doors or gates, installation and repair or replacement costs are excessive.
Another problem experienced with prior art electro-mechanical security locks is that when a power failure is experienced, because of the manner in which the solenoid mechanisms are installed to control the "shot" pin type latching members, a great deal of force is required to release the shot pins. This has required manual locking mechanisms which are controlled by rather large keys which are not compatible with other locks associated with interior passageways within a secured facility. Thus, separate keys must be carried by guards for the outer security gates.
Some examples of prior art electro-mechanical locks and security locks are disclosed in U.S. Pat. Nos. 430,764; 473,061; 1,768,021; 3,142,166; 3,157,042; 3,792,888; 3,953,991; 4,570,466; 4,685,709; 4,993,757 and 5,216,909.